The present invention relates to apparatus for severing webs which consist of paper, cardboard, synthetic plastic material, metallic foil or the like. More particularly, the invention relates to improvements in apparatus for subdividing a running web into sections of desired length, i.e., for severing the web at any one of several frequencies so that the web yields shorter, medium-long or longer sections which can be utilized to form stacks of overlapping leaves or sheets, to constitute blanks for use in the manufacture of cigarette packs or other types of containers for smokers' products, or for other purposes.
It is known to sever a running web of paper or the like by a rotary center which is adjacent to the path of movement of the web and has one or more blades serving to cut across the web at desired intervals. The cutter is driven at a peripheral speed which is identical with the speed of forward movement of the web. Severing apparatus of the just outlined character are known as concurrent cutting devices. They are used in many fields, such as for subdivision of paper webs into sheets or leaves which are thereupon stacked to form note books or pads, in filter cigarette making machines to subdivide adhesive-coated webs into bands which serve to unite plain cigarettes, cigarillos or cigars with filter mouthpiece, in packing machines for cigarettes or the like to subdivide webs of metallic foil, paper, synthetic plastic material or cardboard into blanks which are converted into components of packets, in labelling devices to subdivide a ribbon of labels into discrete labels (e.g., revenue labels for application to cigarette packs) and for a host of other related or unrelated purposes.
A drawback of presently known severing apparatus is that they cannot be readily adjusted when the length of sections which are obtained in response to subdivision of a running web must be changed. Such adjustments are necessary in many industries, e.g., in the tobacco processing industry when the manufacture decides to make cigarette packs of different size and/or shape or when the manufacturer must apply revenue labels whose dimensions deviate from the dimensions of previously used labels. It is also desirable to employ a versatile severing apparatus which can subdivide a relatively wide ribbon, web or strip into sheets or leaves of any desired size. Presently known severing apparatus do not meet such requirements because the intervals of time which elapse during each change of setup are long and the operation is complex, i.e., it must be performed by skilled persons. Moreover, each change in setup involves replacement and adjustment of a substantial number of parts.